Lab 1, 2 And 3 Flashcards
What factors produce RMP?
Na+ K+ ATPase pump
Higher preponderance of K+ nongated
Movement of K out of cell w/ concentration gradient
Big organic ions cannot leave cell
What is RMP
Difference in charge across a cell membrane when a cell is not stimulated
-70mV
How do ion channel proteins function to establish RMP?
Non gated channels allow ions to pass down its concentration gradient
How does the Na+ K+ ATPase pump establish RMP
Uses 1 ATP to produce 3 Na+ out and 2 K + in
What’s a graded potential and what is initially required to produce it
Change in MP usually small deviation from -70
A stimulus
Where do graded potentials occur on a neuron
Dendrites and cell bodies
What would you call generator potential produced on receptors on the skin ?
On inner ear?
At neuronal synapse?
Post synaptic membrane ?
Skin - generator potential
Inner ear - receptor potential
What specific electrical events occur during the production of a graded potential
Opening of gated channels of ions that change RMP
Any except voltage
Depolarization
Hyperpolarization
How is threshold reached at axon hillock
Influx of Na+ fast
In addition to skin which brain structure has thermoreceptors
Hypothalamus
Where in the cerebral cortex is sensory info interpreted ?
Post central gyrus
Sweat is produced what are the effectors and nt released?
Effectors sympathetic ns > ach
If you press the outer corner of your right eye while looking to the left you will see a dark circle surrounded by light near the ridge of your nose, why?
Caused by stimulation of the photoreceptors
This shows that the photoreceptors of the retina may be stimulated mechanically rather than via light, because a light receptor was stimulated
Are there more cold receptors or hot in the body ?
More cold receptors
More detectable in the square test than hot
What instrument was used for the two point discrimination test?
Aesthesiometer
Where on yr body is the two point discrimination greatest ? ie closest together ? Which were farthest apart
Or have more touch receptors
Spatial discrimination
On the finger tip
On the back
When a stimulus occurs on a subject when there eyes are closed and they try to pin point the location
In areas where there are more receptors what would happen
Where inter brain is this stimulus perceived
The localization of the stimulus Is more accurate
Post central gyrus
On the snellen eye chart if you are standing 20 ft away and able to read the letters designated to be read at 20 feet you have
20 / 20 vision
if you can only read the letters designated to be read at 200 feet at 20 (6m) feet then you have
20/200 vision
If astigmatism is present what does the astigmatism chart look like
Some of the spokes will appear sharp and dark while others blurred and lighter
If there is astigmatism and the chart is viewed as if there was one present , what can we deduce about focus of the image
Comes to focus infront of or behind the retina
What causes astigmatism ?
How can you tell if it has been corrected with glasses
The cornea is misshapen
And so the light doesn’t focus correctly on the retina
What does ishihara color plates test
Colourblindness / Deficiencies in color receptors (cones)!
3 cone types which contain diff photoreceptor pigment R,B,G
What is convergence
Medial movement of eyes which helps to maintain partial overlap of the visual field of each eye
What is nystagmus
Involuntary rapid rhythmic movement of one or both eyeballs
What is nystagmus caused by?
Weak extrinsic eye muscles
Or damage to a branch of a cranial nerve that innervates an extrinsic eye muscle
What is a test for convergence ?
Subject focuses on tip of pencil
Slowly brought closer to face from 2 feet to nose
Notice how the pupils constrict
What is a test for nystagmus ?
Hold a pencil 2 feet from nose then move it left to right and up down leaving the pencil at least 10 seconds in each position
Note presence of nystagmus
What does the Rinne test do?
Compares air and bone conduction of sound
Tests for MIDDLE EAR deafness (conductive hearing loss)
How does air conduction of sound happen
Sound vibration pass from auricle to inner ear via tympanic membrane and middle ear ossicles
How does bone conduction of sound work
Vibrations are passed through bones of skull to inner ear
Normally bone conduction not as sensitive as air
How would we conclude that there is an impairment of fiction of external ear (wax) or middle ear ossicles (causing middle ear deafness)
If the bone conduction of sound is better heard by the subject than air during the rinne test
What is the Weber test for ?
Middle ear deafness (conductive hearing loss) Nerve defects (sensorineural hearing loss)
How to do the weber test
Stike tuning fork and place the handle infront of subjects forehead
Ask if there is a difference in sound intensity in either ear
To simulate inner ear deafness plug one ear
If the sound intensity is greater in one ear or the other what does that mean for the weber test
A CHL in ear that perceives sound louder BECAUSE in middle ear deafness there is no environmental noise to interfere with sound heard by bony conduction
Or
Possible nerve defects in opposite ear
What does the light pupillary reflex demonstrate
The light constricts pupil affected
And the other pupil consensually constricts
What’s the consensual light reflex
When a pupil constricts in conjunction with the pupil being affected by light stimulus
The pupillary light reflex is ____lateral
Ipsilateral
The consensual light reflex is _______lateral
Contralateral
What is the ciliospinal reflex
Examine pupillary response
Illuminate left side of face (constrict)
Scratch skin on left side o neck
Ipsilateral pupil dilation occurs
What branch of NS causes the left iris to increase in the ciliospinal reflex
Sympathetic
What is corneal reflex
Bilateral blinking when sclera is touched
During the knee jerk reflex what happens when the subject is distracted
Response is greater
What happens to patellar reflex when subject is fatigued
Patellar reflex less vigorous
Ankle jerk (Achilles' tendon reflex) What happens
After striking Achilles’ tendon with patellar hammer
Tendon will stretch gastrocnemius muscle to contract
Plantar flexion of foot
For plantar reflex( babinski )
How is the procedure done
Socks removed heels braced
Dissecting needle traced from heel to toes
If reflex normal toes will curl
If not plantar reflex replaced by babinski > toe dorsiflex and toes fan out
When is babinski reflex usually done ?
Obtained in infants up to the age of 6 months sometimes up to 5
(Physiological babinski)
In adult reflex normally absent but may occur in sleep
In epileptics following a seizure or if there is damage to corticospinal tracs (upper motor neurons)
How could we test the femoral nerve
Cranial nerve VII (facial)
Cranial nerve VIII (vestibucochlear)
F- patellar
VII- corneal
VIII- rinne / weber
Definition of blood pressure
The pressure blood exerts against any unit area of the blood vessel walls generally measured in arteries
Systolic reading of BP is
The pressure in the arteries at the peak of ventricular ejection
Diastolic pressure is
The pressure in the arteries during ventricular relaxation
BP is measured in
Multimeters of mercury
mm Hg
How does a sphygmomanometer measure BP
What is it
The ausculatory method
Inflatable cuff with a pressure gauge
What are sounds of korotkoff
The sounds heard from the stethoscope which indicate the resumption of blood flow in the brachial artery
First soft tapping sounds is systolic
The pressure at which the sounds of korotcoff disappear are the
Diastolic pressure
What is the pulse pressure
Systolic - diastolic
What is the mean arterial pressure
The average pressure in the systemic arteries
The product of cardiac output and total peripheral resistance
MAP = PP/3 + diastolic
What is p wave
Atria depolarization
What is QRS wave
Depolarization ventricles
Repolarization of atria over shadowed
What Is T wave
Repolarization of ventricles
How can you calculate BPM or heart rate from ECG/EKG?
You measure the distance in mm between each QRS wave
Divide the QRS / chart speed
Divide result by 60sec
How can you calculate the amount of beats jn a second ?
Divide chart speed by distance between beats
Where would we put the stethoscope if we want to hear the first sound of the cardiac cycle
Apex
On the 2nd intercostal space or 2-3 cm below the clavie and left to the sternum what sound should you be able to hear clearly
Second sound of cardiac cycle dub
Is it normal that inspiration increases during inspiration and decreases during expiration
Yes
What is laminar flow
Non turbulent or stream line flow
What is turbulent flow
Erratic flow of blood
Compressed artery
What events cauSe the first and second heart sounds
Turbulent blood flow 1) against closing of AV valves
2) closing of semilunar valves
Hydrostatic vs osmotic
Hydro - push
Osmotic - pull
What coordinates the RAS
Hypothalamus
In the luteal phase progesterone is released from the corpus luteum, what does the progesterone inhibit first and as a result of that what else does it inhibit ?
GnRH
FSH / LH
What does exocytosis require
Calcium
During depolarization , when threshold potential is reached, depolarization of the membrane becomes self generating therefore
Is positive feedback mechanism
Na+ permeability when all channels open 1000 times greater than resting neuron
Repolarization what happens to K+ and Na+ channels
Na+ close
K+ open following it’s electrochemical gradient (ie now the inside is more positive than the outside )
What happens to ion channels during hyperpolarization
Some k remain open (period of increased K permeability)
Na+ reset
Excessive K efflux makes cell ultra negs
